individual deletion mutants of tauR, tauC, and tauY, show growth defects. Growth is restored when each mutant is complemented with the appropriate gene on a plasmid, suggesting that the individual deletions do not deter expression of downstream genes, they are not polar mutations. Induced or uninduced DELTAtauY mutant displays the highest levels of reporter expression compared to other strains grown under similar conditions. Increased accumulation of taurine, and thus enhanced expression, occurs in the DELTAtauY mutant due to its inability to degrade the sulfonate compound

the genes of the tau region, tauR, tauC, and tauY, are each required for taurine dissimilation in Sinorhizobium meliloti. Enzyme TauY is involved in the degradation of taurine, most likely by forming part of the taurine dehydrogenase

in-frame deletion of gene tauY. Individual deletion mutants of tauR, tauC, and tauY, show growth defects. Growth is restored when each mutant is complemented with the appropriate gene on a plasmid, suggesting that the individual deletions do not deter expression of downstream genes, they are not polar mutations. Induced or uninduced DELTAtauY mutant displays the highest levels of reporter expression compared to other strains grown under similar conditions. Increased accumulation of taurine, and thus enhanced expression, occurs in the DELTAtauY mutant due to its inability to degrade the sulfonate compound